The next time we go, our princess will be 19 months old!
As for tips, I will just tell you to GO WITH THE FLOW. Don't rush around commando or anything, just make sure to take it at the 1 year olds pace.
A one year old can do PRACTICALLY EVERYTHING at WDW (except for a few thrill rides, and you guys can do child swap to make sure you all get to ride everything!) Make sure you have your nice comfortable stroller so she can take naps when she gets tired. The plastic ones at WDW are VERY HARD and definitely not that comfortable!
If the 1 year old gets out of control, take her back to the resort in the middle of the day for a break...some quiet time and maybe even a quick nap. Then bring her back to the parks for the latter part of the day.
DON'T WORRY, EVERYTHING WILL BE GREAT!!!!!!!!